The present invention relates to a process for the preparation of optionally substituted (N-heterocyclyl) aryl ethers.
Various (N-heterocyclyl) aryl ethers are already of importance as intermediates for the synthesis of medicaments and agrochemicals and are an essential structural element in active ingredients against e.g. infectious diseases, schizophrenia, depression, neurodegenerative diseases and also in pesticide intermediates.
Various processes for the preparation of (N-heterocyclyl) aryl ethers are known.
Thus, for example, WO 2005/092832 describes the preparation of (N-heterocyclyl) aryl ethers, in particular of an aryl piperidinyl ether, starting from N-boc-4-hydroxypiperidinol via a complex three-stage synthesis. The same is true for WO 97/23216.
Alternatively to this, in EP 1947098 A1, the synthesis takes places starting from N-benzyl-4-hydroxypiperidinol with the introduction of a protective group and reaction with 4-trifluoromethyl-fluorobenzene, which has considerable disadvantages in the economic feasibility.
The preparation of an(N-heterocyclyl) aryl ether is described in WO 2002/072621 starting from N-boc-4-hydroxypiperidinol via a Mitsunobu reaction using diethyl azocarboxylate (DEAD). This route is difficult to realize on account of the explosivity of the DEAD used, especially on an industrial scale.
The known processes have the disadvantages that they are either uneconomical, ecologically unacceptable or problematic from a safety aspect.
It was therefore the object to provide a process which does not have the disadvantages of the processes hitherto and produces the (N-heterocyclyl) aryl ethers in good yields, in a cost-effective manner on an industrial scale.